1. Field of the Invention
This invention relates to a continuous process for the production of hydrogen-rich gas. More specifically, the present invention pertains to reacting a stream of raw synthesis gas in a multi-bed catalytic water-gas shift converter to increase the hydrogen content.
2. Description of the Prior Art
Hydrogen gas may be obtained by the catalytic reaction of carbon monoxide and steam. This reaction is exothermic, liberating approximately 16,400 Btu per mole of carbon monoxide converted. It is commonly referred to as the water-gas shift reaction and is shown in Equation 1 below. EQU CO + H.sub.2 O .fwdarw. CO.sub.2 + H.sub.2 ( 1)
a typical conventional water-gas shift catalyst is iron oxide promoted by chromium oxide. This catalyst is referred to commonly as a high temperature shift catalyst because it has an ignition temperature in the range of about 600.degree. to 710.degree. F. The effluent gas stream leaving a reaction zone containing high temperature shift catalyst is at a temperature in the range of about 715.degree. to 1000.degree. F.
CrO.sub.2 promoted Fe.sub.2 O.sub.3 shift catalyst is relatively low priced, readily available, and its strength is high at the high temperatures which exist at the exit of the catalyst bed. However, a serious disadvantage is that the reaction rate of iron oxide catalysts at low temperatures is comparatively slow. Accordingly, the inlet temperature of the reactants must be at a minimum of about 600.degree. F.